Probing the diamagnetic term in light–matter interaction

We address the quantum estimation of the diamagnetic, or A 2 , term in an effective model of light–matter interaction featuring two coupled oscillators. First, we calculate the quantum Fisher information of the diamagnetic parameter in the interacting ground state. Then, we find that typical measurements on the transverse radiation field, such as homodyne detection or photon counting, permit to estimate the diamagnetic coupling constant with near-optimal efficiency in a wide range of model parameters. Should the model admit a critical point, we also find that both measurements would become asymptotically optimal in its vicinity. Finally, we discuss binary discrimination strategies between the two most debated hypotheses involving the diamagnetic term in circuit QED. While we adopt a terminology appropriate to the Coulomb gauge, our results are also relevant for the electric dipole gauge. In that case, our calculations would describe the estimation of the so-call… …

Read More...

Comments Off on Probing the diamagnetic term in light–matter interaction

Nanotechnology: Lighting up ultrathin films

Based on a study of the optical properties of novel ultrathin semiconductors, researchers have developed a method for rapid and efficient characterization of these materials.

Read More...

Comments Off on Nanotechnology: Lighting up ultrathin films

Seeing the quantum future

Scientists have demonstrated the ability to ‘see’ the future of quantum systems and used that knowledge to preempt their demise, in a major achievement that could help bring the strange and powerful world of quantum technology closer to reality.

Read More...

Comments Off on Seeing the quantum future

‘Weak measurement’ with strong results

A new method has been developed allowing for quick and precise measurement of quantum states.

Read More...

Comments Off on ‘Weak measurement’ with strong results

New microscope chemically identifies micron-sized particles

Scientists have developed a microscope that can chemically identify individual micron-sized particles. The new approach could one day be used in airports or other high-security venues as a highly sensitive and low-cost way to rapidly screen people.

Read More...

Comments Off on New microscope chemically identifies micron-sized particles

Robust quantum state transfer via topologically protected edge channels in dipolar arrays

We show how to realise quantum state transfer between distant qubits using the chiral edge states of a two-dimensional topological spin system. Our implementation based on Rydberg atoms allows to realise the quantum state transfer protocol in state-of-the-art experimental setups. In particular, we show how to adapt the standard state transfer protocol to make it robust against dispersive and disorder effects. …

Read More...

Comments Off on Robust quantum state transfer via topologically protected edge channels in dipolar arrays

Theory provides roadmap in quest for quark soup ‘critical point’

Thanks to a new development in nuclear physics theory, scientists exploring expanding fireballs that mimic the early universe have new signs to look for as they map out the transition from primordial plasma to matter as we know it. The theoretical work identifies key patterns that would be proof of the existence of a so-called “critical point” in the transition among different phases of nuclear matter.

Read More...

Comments Off on Theory provides roadmap in quest for quark soup ‘critical point’

Electrons ‘puddle’ under high magnetic fields

Researchers have used extremely high magnetic fields — equivalent to those found in the center of neutron stars — to alter electronic behavior. By observing the change in the behavior of these electrons, scientists may be able to gain an enriched understanding of material behavior.

Read More...

Comments Off on Electrons ‘puddle’ under high magnetic fields